How Many Violent (EF4/EF5) Tornadoes In Wisconsin? (updated 05/23)

EF5/F5 tornadoes are rare in Wisconsin. We took a look in the record books going back into the 1800s and could find only 6 tornadoes which could be considered EF5/F5.

Two of them (Oakfield in 1996 and Barneveld in 1984) were officially documented as EF5/F5 strength. These two are listed below along with the other candidates.

Keep in mind the National Weather Service officially started to rate the strength of tornadoes in 1982. A commercial business (Thomas Grazulis) was contracted by the NWS to rate tornadoes in the U.S. between 1950 and 1981 based on documented descriptions and pictures. Additionally, Grazulis rated tornadoes prior to 1950 as well, but these pre-1950 tornado ratings are considered unofficial.

The National Weather Service has documented 1499 tornadoes in Wisconsin going back to 1844. Documentation prior to 1950 was incomplete. The six EF5/F5 tornadoes equate to roughly 0.4 percent of all documented tornadoes in Wisconsin. Additionally, we've documented at least 511 fatalities and 3049 injured people in Wisconsin due to tornadoes.

Baldwin to Colfax area/St. Croix and Dunn County. June 4, 1958. 630 to 710 pm. Path length 34.8 miles, max width 880 yards. Killed 19 and injured 10. Moved at 52 mph from south of Woodville to east of Colfax. Not officially rated by the NWS. Rated as a F5 by a company contracted by NWS.

New Richmond /St. Croix County. June 12 1899. Started 540 pm. Path length 45 miles, max width 300 yards. Killed 117 and injured 125 and destroying over 300 buildings. Not officially rated by the NWS, but many people agree this was probably a F5 tornado.

The map below shows the EF5/F5 rated tornadoes across the United States since 1950. The tornadoes are numbered in the order that they occurred since 1950, from lowest to highest. This graphic is courtesy of the Storm Prediction Center. Click on image for a larger version.

Below is a list of the 40 EF4/F4 tornadoes that have occurred across Wisconsin since the late 1800s. Some of these tornadoes may have been two or three tornadoes, but available documentation doesn't allow for additional refinement. Note that the tornadoes rated as F4s prior to 1950 were approximated by Thomas Grazulis. These ratings, based on documentation and pictures, are considered unofficial. The 40 tornadoes rated potentially at EF4/F4 constitute roughly 2.7 percent of all documented tornadoes in Wisconsin going back to 1844.

Tornadoes rated as EF5/F5 or EF4/F4 are considered violent tornadoes, and are the tornadoes responsible for most fatalities related to tornadoes. In Wisconsin, we've potentially had six EF5/F5 tornadoes and forty EF4/F$ tornadoes for a total of 46, or roughly 3.1 percent of the 1499 documented tornadoes in the state going back to 1844. Again, documentation prior to 1950 was incomplete, especially in the 1800s.